If your friend borrowed your dog and a biting incident occurred, he or she is liable for any damages. Under the common law, the keeper of the dog at the time of the attack is the liable party. By definition, the “keeper” is someone who has temporary care of the dog or has the dog under his or her care and custody. However, this ruling varies per state. In California, the strict liability rule does not apply to the keeper.
However, if the owner knew that the dog has the tendency to bite people, has bitten people before, or has been known to be violent and did not inform his friend, then the owner is liable.
The owner and the keeper can avoid liability if the bite victim provoked the dog or triggered the attack. If the victim is under the veterinarian rule, there is an assumed risk of an attack, then the owner is not liable.
It is also possible for companies, agencies, and landlords to be held liable due to negligence. For instance, if a landlord who leased his house to a dog-owner, knew that the dog had dangerous propensity, he may also be liable.